Born Samuel Sterns in Boise, Idaho, he worked for a chemical plant in a menial capacity. While moving radioactive materials into an underground storage area, some of the radioactive materials exploded, bombarding Sterns with gamma radiation. He recovered, and found that the radiation had changed him from an ordinary human into a green-skinned, super-intelligent entity with an oversized brain housed in a towering cranium.[5] As was the case with most individuals mutated by gamma radiation early-on, the particular set of characteristics Sterns acquired by exposure to it were said to result from a subconscious desire; in his case, the desire to be as smart as his brother Philip, who was a physicist in the employ of the same facility. Calling himself the Leader, Sterns embarked on various ambitious criminal schemes, with the Hulk as his primary nemesis, consistently backed by a self-constructed army of super-strong, virtually invulnerable plastic Humanoids. These included an attempt to rewrite the Earth's history by infecting the primordial ooze with gamma radiation in order to recreate society in his image, with himself as its ruler.[volume & issue needed]

The Leader began his career as a would-be conqueror by creating a spy ring to overthrow the United Statesfederal government. The Leader sends a spy to steal a robot Banner was developing. Banner goes after the spy but turns into the Hulk. The spy overpowers an unsuspecting watchman, leaving him bound and gagged while he gets into the robot and drives it to the test. A guard finds the watchman who reports he was knocked out, however they can't bring down the robot, and neither can the Hulk. The spy finds Banner's caves and makes a missile to fire at the base. Finally in the caves Hulk knocks the robot into a deep pit, killing the spy. He then stopped the missile.[6] The Leader then dispatched his ally the Chameleon to capture the Hulk for study by impersonating Bruce Banner.[7] Although the Chameleon failed, the Leader succeeded in capturing the Hulk by sending a horde of Humanoids to subdue him.[5] He also succeeded in stealing the Absorbatron, a device invented by Banner that could absorb the energy of a nuclear explosion, and thereby render any nation that possessed it immune to nuclear attack.[8] The Hulk eventually escaped the Leader and destroyed most of his lab, along with the Absorbatron, but the Leader himself escaped.[9] Eager to sell his Humanoids to hostile nations, the Leader gave a demonstration of his power by activating a 500-foot (150 m)-tall Humanoid and ordering it to attack a nearby missile base. The Hulk eventually encountered the Humanoid and managed to thwart the Leader's plans.[10] Curious to learn more about the power of the Hulk, the Leader then rescued the Hulk from the Army, who had cornered the monster in a cave.[11] After operating on the Hulk to save his life, the Leader reminded the Hulk that he was in his debt. Using this leverage, the Leader sent the Hulk to the homeworld of the Watcher to raid the Watcher's "Ultimate Machine", a device containing all the knowledge in the universe.[12] However, this huge amount of knowledge proved too much for the Leader. He collapsed to the ground, unmoving, and the Hulk assumed that he died of shock.[13] General Ross soon discovered the Leader's abandoned base and accidentally activated the "Hulk Killer" a large Humanoid designed to defeat the Hulk.[volume & issue needed]

Later, the Leader reappeared and offered General Ross aid in neutralizing the Hulk.[14] The Leader dispatched the Super-Humanoid to assist the General in seizing control of America's nuclear arsenal.[15] The Leader then hijacked the U.S. Army's Murder Module vehicle, and used it against the Hulk.[16] He freed the Rhino from captivity and sent him against the Hulk.[17] After briefly turning back into Samuel Sterns to question Banner about the Hulk's possible weaknesses, he resurrected the Glob to try to pit him against the Hulk.[18] The Leader later sent mental projections of the Rhino, Xeron, Namor, the Missing Link, and others against the Hulk, but then suffered a mental breakdown.[19] The Leader then created android duplicates of the President, Vice President, and military personnel in an attempt to kidnap the real President and Vice President.[20] He then superimposed his consciousness upon the Rhino in order to battle the Hulk.[21] He later used the Hulk and the Thing as pawns in a contest with Kurrgo.[22]

Some time later, the Leader briefly took over Gamma Base.[23] Some time after that, he gamma-irradiated Manhattan's water supply in an attempt to mutate humanity like himself.[24] He later activated Arsenal, and then dispatched the Avengers through time.[25]

After a period of time, the gamma radiation in his body began to wear off. At first, the Leader attributed his lapses in concentration to overworking his mind finding ways to defeat his greatest enemy (the Hulk). By the time the Leader realized what was happening, much of the intelligence that could have solved his plight was gone and texts that were once child's play to him were now hopelessly beyond him (he even forgot the access code of his secret base). In this period, he made cash however he could by means fair or foul, until he managed to convince the Gray Hulk to help him regain his intelligence by promising that he would help the latter to remain the Hulk full-time (instead of only at night).[volume & issue needed]

Rick Jones had been afflicted with a Hulk-like condition and the Hulk (using Bruce Banner's memories of gamma transfer) devised a machine to transfer all of the gamma radiation from Rick Jones to the Leader. However, this time the mutagenic process was slightly different resulting in a cranium that resembled an over-sized brain, rather than a towering forehead. He was also a lighter shade of green. As a side note, this transfer also created a psychic link between the two.[26]

Soon after this, the Leader would steal the seemingly lifeless body of General Thunderbolt Ross from the back of an ambulance, simply because it was there, and later managed to revive it as a mindless vegetable, which he used as an armored enforcer.[27]

Before long, the Leader's new form was revealed, and he dispatched Half-Life to battle the Hulk.[26] The Leader dispatched an army of four-armed robots against the Hulk, and created Rock and Redeemer.[28]

The Leader dispatched Rock and Redeemer against the Hulk. Following this the Leader engaged in a scheme to detonate a gamma-bomb in a small-town city, Middletown, Arizona, killing over 5,000 people, and the few, now enhanced, survivors provided him with valuable research subjects and superhuman enforcers called the Riot Squad.[29] With their help, he built a self-sufficient society called Freehold in the Arctic, populated with civilians dying from radiation poisoning. Some time afterward he gave the Hulk information how to find his brother, Philip Sterns, the Madman, since he thought it would be best to put the latter out of his suffering, due to his original personality being slowly and painfully eaten away by the Madman persona.[30]

After Jones suffered a great mental trauma due to the death of his girlfriend Marlo Chandler, his pain was enough to cause the Leader considerable discomfort, motivating him to work towards the revival of Marlo. At this time Freehold was targeted by a rogue branch of HYDRA terrorists, employing the U-Foes and his followers to invade the covert Pantheon organization, of which Hulk was a member, to coerce them to help him in defending it. He employed something he ironically called the Deus Ex Machina in conjunction with his follower, the gamma-enhanced reverend nicknamed Soul Man, who falsely believed himself to have been blessed by God with spiritual power, rather than given nearly godlike abilities by the Leader, in an effort to revive Marlo and siphon off Soul Man's power for himself. Rick Jones became convinced to accept the help after seeing the mindless, but mobile, body of Thunderbolt Ross.[31]

The Hulk, manipulated by the leader of the Pantheon, Agamemnon, attacked the facility. At the same time, HYDRA decided to storm the base, leading to a multi-sided battle. The Hulk eventually personally attacked the Leader, who, along with Soul Man, seemingly perished in the crossfire. The machine was likewise demolished, causing Marlo to enter a state similar to Ross, but both eventually fully recovered.[27]

The death of the Leader left his follower Omnibus in control of Freehold. Omnibus used mind-control to manipulate several U.S. chiefs of staff, and engineered many high-profile terrorist strikes to incite global warfare, as he reasoned that it was inevitable, and hurrying it along offered him opportunity to enable his personal society to survive and inherit the Earth. Omnibus was eventually exposed by his fellow Freehold citizens, judged to die in the cold, and was eaten by a polar bear.[32] Bruce Banner also saw the Leader in a supposed trip to Hell.[volume & issue needed]

A while later, the Hulk, who in his Bruce Banner persona was suffering from a degenerative nervous condition (which would ultimately kill him) was confronted by the Leader once again. Apparently he really had perished when the Deus Ex Machina was destroyed, but his disembodied consciousness had evolved beyond the need for a body. Although he was in the process of building a new body out of random organic materials, in a secluded cave near Gamma Base, he was preparing to leave this level of reality behind altogether, transcending both beyond the physical and his old goals. Yet before he did so, he intended to cure Bruce Banner for reasons all his own. After he had done so, he abandoned his body. However, later still his consciousness once again contacted Banner, apparently shocked by what he had discovered "beyond the veil"; he was unable to return, however, and was not heard from again until much later.[33]

During a time of great personal duress for the Hulk and Bruce Banner, who had begun to merge their personas, it became clear that Home Base, a secret organization who had relentlessly pursued the Hulk in order to obtain his genetic material, was secretly led by the Leader. In the end, after all his other agendas had failed, the Leader finally managed to mind-control the Hulk and guided him towards his secret base, with the intention of taking his indestructible body for himself. Because of intervention by Nadia Blonsky, Betty Ross, Doc Samson, and Iron Man, the plan failed and the Leader died again.[34]

These events, bizarre and nebulous as they seem, may or may not have taken place in this form... they may be partly true, or entirely a construct by the extra-dimensional demon Nightmare in a bid to avenge himself on the Hulk.[volume & issue needed] At present, the Leader has a body incorporating traits from both his previous incarnations; it is unknown exactly how he acquired it, but it may have been relatively easy, given his history.[volume & issue needed]

The Leader is captured by S.H.I.E.L.D.'s Hulkbusters, and brought to trial for his crimes. He was represented by Attorney Mallory Book from She-Hulk's firm Goodman, Lieber, Kurtzberg & Holliway. During the trial, Ms. Book argued that the Leader was not responsible for his actions since the Gamma exposure forcibly changed his personality. To prove her point, Book compared She-Hulk to Jennifer Walters, revealing that Jennifer was much more promiscuous in her She-Hulk form. In the second day of the trial, Leader's humanoid droids arrived to rescue him. Instead of escaping, the Leader called off the attack, opting to see the trial to its conclusion, as he correctly predicted that his defense was going to win. He was found not guilty.[35] It is as yet unclear whether this person is indeed the original Leader, or the Samuel Sterns of "Earth-Alpha", the inhabitants of which had been swapping places with their 616 counterparts for a while prior to this trial.

Now a free man (whichever one he may be), the Leader teleported the Hulk's allies, the Warbound, to Nevada. There, he used Hiroim of the Warbound, harnessing his tectonic power to activate a gamma powered shield over a portion of the desert. It is revealed that the Leader is dying, and that he constructed the dome to cure him. Due to a miscalculation, the energy of the dome actually kills him faster.[36] In battle with the Warbound, the Leader is stabbed through the chest with an iron pipe. The Leader then absorbed the power of the dome, turning himself into a gray-skinned giant. Hiroim also absorbed the power, and battled the Leader, draining both of their powers. In death, Hiroim channels his old power into Kate Waynseboro, who attacks the Leader, and forces him to teleport away.[37]

The Leader, apparently healthy and in the form he originally had, appears once again, this time with designs on the Hulk's son Skaar. It is eventually revealed that he, along with a select group of genius super-villains, is part of a longtime collaboration he calls The Intelligencia.[38] Leader was also responsible for mutating Marlo Chandler into the new Harpy. During that time, he planned revenge on Kate Waynesboro.[39]

At the conclusion of the Red Hulk storyline, a newly rejuvenated Red Hulk approaches the Leader and gets close enough to him to completely drain the body-altering gamma radiation from the Leader's physiology. Red Hulk does this as a punishment for the Leader's altering of Ross's/Red Hulk's daughter into the Red She-Hulk. Red Hulk leaves Sterns alive to suffer, reminding him that as the person he has been reverted to with his original, well below average intelligence, Sterns will never be able to duplicate a gamma-infusion and return his powers as The Leader... at least not on his own.[40]

A powerless Leader is later seen in custody demanding "gamma" (the one thing no one is willing to give him) if he was to divulge any information on stopping the Intelligencia's failsafe doomsday plans.[41]

At the end of the second issue of the new Thunderbolts series as part of the Marvel NOW! event, a powerless Samuel Sterns is seen apparently housed within a shipping container. His head is connected to a machine apparently emitting red gamma radiation (in the fashion of the Red Hulk) with the harness in the shape of the Leader's formerly tall head. Samuel Sterns is apparently in the custody of Red Hulk.[42] During the third issue, Samuel Sterns has reddish hued skin, but with no apparent powers. Once Deadpool sees that the Red Hulk is employing Samuel Sterns, he expresses his view that the Punisher will not be pleased. As soon as the Punisher sees Samuel Sterns, he shoots him right between the eyes, killing him and the Red Hulk's plan.[43] During the fight against Madman, Red Hulk took him to a pipe line that feeds Gamma energy to Madman's lab.[44] Red Hulk then absorbed the energy himself and then force fed it to the Leader, bringing him back to life.[45] Leader then joins the Thunderbolts under the new alias Red Leader.[46]

The Leader has superhuman mental acumen, as a result of his exposure to an explosion of gamma-irradiated waste. He possesses enhanced intuition, pattern solving, information storage and retrieval, and logical and philosophical structuring. His ability to predict probable outcomes of tactical and strategic scenarios is so advanced that it borders on clairvoyance. The Leader has a perfect memory with the ability to recall every moment since the accident that gave him his powers. In addition to his superhuman intelligence, the Leader has limited but potent telekinetic and telepathic powers. He is able to mentally control non-gamma-mutated individuals upon touching them, and has toppled a very weakened Hulk with his telekinetic blasts.

The Leader possesses knowledge of genetics, physics, and robotics, and has designed a large number of sophisticated weapons, vehicles, computers, androids, and synthetic humanoids. He is particularly adept at genetic engineering and manipulating radiation for various nefarious purposes.

On occasion, the Leader showed the ability to turn himself back into Samuel Sterns, but this ability resulted in him losing all memory of his identity as the Leader as Sterns's mind was ill-equipped to cope with the Leader's intellect (although he always remembered everything when he turned back into the Leader again).

Prior to the release of The Avengers in 2012, Marvel ran a series of canon tie in comics entitled "Avengers Prelude: Fury's Big Week", which take place within the Marvel Cinematic Universe. In issues 6 and 7, Sterns is seen undergoing a rapid head mutation just as he is discovered by Natasha Romanoff who stumbles upon him immediately after Hulk has escaped. Although his brainpower has already drastically increased to the point where he can pinpoint the exact location of Black Widow's birth just by a brief hint of Stalingrad in her accent, Natasha shoots him in the leg when he attempts to bribe her by offering to help her return to her home and he is detained into S.H.I.E.L.D. custody.[47]

The Leader makes an appearance as a zombie in Marvel Zombies vs. The Army of Darkness in the horde that overwhelms and infects the Punisher. He has a giant hole blown through his cranium which does not stop him.[48] He is also in Marvel Zombies 3 where he is looking over food and medical supplies that other zombies have found as an offering to a zombie Kingpin. The Leader determines how long the others can feed on the human clones. The Leader is sent with other zombified superbeings to find and destroy the Machine Man. The android gains the upper hand in the battle and destroys all his pursuers. The Zombie Leader then kills himself by ripping out his arm, using it to take out all of his brain, and ripping out his own body.[49]

The Ultimate version of Leader made his first appearance in Ultimate Human #1, a miniseries starring Ultimate Iron Man and Ultimate Hulk.[50] This Leader is also the Ultimate version of MI6 agent Pete Wisdom. In the Ultimate universe, Wisdom is an ex-British Intelligence agent thrown out of the organization after testing his "British Enhancile Program" on himself, transforming him into The Leader.[51] Wisdom has psychic and mental abilities similar to the original Leader, but requires a wheelchair and a halo brace to support the weight of his enlarged cranium. The Leader attempts to steal Tony Stark's nanotechnology as Banner and Stark work together to try to incorporate it into Banner's physiology in the hopes that it will grant him control over his transformations into the Hulk. When Stark commands a decoy Iron-Tech robot into the base of the Leader, Banner transforms into the Hulk. The Hulk resists the Leader's influence, and pounds him into the ground. The Leader, almost dead, commands an C-17 down onto the Hulk, ultimately killing Wisdom/Leader.[52]

The Leader is featured as a recurring villain in the 1990s UPNIncredible Hulk series, with Matt Frewer reprising his role. He is served by Gargoyle, Abomination, Ogress, and the Gamma Warriors (whom were created from Hulk's DNA).

The Leader cameos in The Super Hero Squad Show episode "Tremble at the Might of MODOK". He is shown at a convention of evil geniuses.

Dr. Samuel Sterns appears in the film The Incredible Hulk, portrayed by Tim Blake Nelson. In this film, he is a university professor trying to help Bruce Banner find a cure for his transformations, while operating under the alias of "Mr. Blue". After turning Emil Blonsky into the Abomination, some of Hulk's blood drips into an open head wound causing his cranium to rapidly expand as he grins maniacally.

The Leader appears as the main villain in the Hulk video game (which picks up after the movie of the same name), voiced by Michael Dobson. In this game, he planned on creating an army from Gamma Radiation to help him take over the world using a special "Gamma Orb" along with help from his brother Madman and fellow enemies of the Hulk such as Ravage and Halflife.

Dr. Sterns appears in The Incredible Hulk video game, with Tim Blake Nelson reprising his role from the film.